Phase Equilibria of {Carbon Dioxide + Acetone + Dimethyl Sulfoxide} Systems: Experimental Data and Thermodynamic Modeling

Dimethyl sulfoxide (DMSO) and acetone are frequently used in supercritical antisolvent (SAS) processes, since they have very different physical properties and have complex phase behavior. This paper reports experimental phase equilibrium data for {CO2 + DMSO} and {CO2 + acetone + DMSO} systems. The static synthetic method was employed to obtain phase equilibrium behavior in pressures up to 12.1 MPa, temperature range between 313.15 and 343.15 K, the concentration of 5.5 mol·kg−1 (solute: DMSO; solvent: acetone) on a CO2-free basis, and CO2 mole fractions between 0.652 and 0.953. The experimental data measured here presented transitions of VLE (vapor–liquid equilibrium) and LLE (liquid–liquid equilibrium) phases. In this work, the effects of association between molecules are considered. Thus, the PC-SAFT EoS was used to model the experimental data and phase transitions, and the pressure deviation between experimental and calculated data for the binary and ternary system was 0.81% and 0.51%, respectively. The percentage average absolute relative deviation (%AARD) for {CO2 + DMSO}, {CO2 + acetone} and {DMSO + acetone} system was 0.57, 0.89 and 0.29, respectively.